{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,27]],"date-time":"2025-11-27T02:51:16Z","timestamp":1764211876448,"version":"build-2065373602"},"reference-count":21,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2014,10,16]],"date-time":"2014-10-16T00:00:00Z","timestamp":1413417600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Single-molecule pH sensors have been developed by utilizing molecular imaging of pH-responsive shape transition of nanomechanical DNA origami devices with atomic force microscopy (AFM). Short DNA fragments that can form i-motifs were introduced to nanomechanical DNA origami devices with pliers-like shape (DNA Origami Pliers), which consist of two levers of 170-nm long and 20-nm wide connected at a Holliday-junction fulcrum. DNA Origami Pliers can be observed as in three distinct forms; cross, antiparallel and parallel forms, and cross form is the dominant species when no additional interaction is introduced to DNA Origami Pliers. Introduction of nine pairs of 12-mer sequence (5'-AACCCCAACCCC-3'), which dimerize into i-motif quadruplexes upon protonation of cytosine, drives transition of DNA Origami Pliers from open cross form into closed parallel form under acidic conditions. Such pH-dependent transition was clearly imaged on mica in molecular resolution by AFM, showing potential application of the system to single-molecular pH sensors.<\/jats:p>","DOI":"10.3390\/s141019329","type":"journal-article","created":{"date-parts":[[2014,10,16]],"date-time":"2014-10-16T10:34:40Z","timestamp":1413455680000},"page":"19329-19335","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":56,"title":["Nanomechanical DNA Origami pH Sensors"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0003-2996","authenticated-orcid":false,"given":"Akinori","family":"Kuzuya","sequence":"first","affiliation":[{"name":"Department of Chemistry and Materials Engineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan"},{"name":"PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi,  Saitama 332-0012, Japan"}]},{"given":"Ryosuke","family":"Watanabe","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Materials Engineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan"}]},{"given":"Yusei","family":"Yamanaka","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Materials Engineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan"}]},{"given":"Takuya","family":"Tamaki","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Materials Engineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan"}]},{"given":"Masafumi","family":"Kaino","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Materials Engineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8862-850X","authenticated-orcid":false,"given":"Yuichi","family":"Ohya","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Materials Engineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan"}]}],"member":"1968","published-online":{"date-parts":[[2014,10,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"237","DOI":"10.1016\/0022-5193(82)90002-9","article-title":"Nucleic-acid junctions and lattices","volume":"99","author":"Seeman","year":"1982","journal-title":"J. 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